Answer:
The correct option is C.
Step-by-step explanation
Option A
Amines are the organic compounds which contain amino functional groups (-NH2), i.e 1-Propamine (CH3-CH2-CH2-NH2). so this is incorrect option.
Option B
Phosphate group is present in group of organic compounds known as organic phosphates. they are involved in energy transfer reaction. the best example is ATP. This option is also incorrect.
Option C
option C is correct because Acetic acid belongs to a group of organic compounds known as carboxylic acids. Carboxylic acid is characterized by the presence of carboxyl functional group (-COOH).
Conclusion
it is concluded that acetic acid contains carboxyl group.